Ultrasmall superparamagnetic iron oxide particles for biomedical applications

Ultrasmall superparamagnetic iron oxide (USPIO) particles are iron oxide nanoparticles currently used for Biomedical applications: contrast agents in magnetic resonance imaging, drug delivery systems, etc. The coatings surrounding the USPIO inorganic core may control the in vitro stability and the in vivo fate. Different physicochemical properties such as the final size, the surface charge and the density of coverage are key factors in this respect. A complete physicochemical characterization of USPIOs particles is difficult due to their small dimensions. However, such a characterization is necessary to improve the stability of the particles and their in vivo behaviour. This review is focused on the techniques which can be applied to have a better insight in the magnetic core structure of these particles and their organic surface.